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. Author manuscript; available in PMC: 2022 Nov 25.
Published in final edited form as: Addiction. 2021 Dec 5;117(5):1458–1471. doi: 10.1111/add.15746

Figure 1. Study design.

Figure 1

Note: a) The dashed arrow represents the negative control analysis. Assumption includes: the same confounders influence maternal and paternal prenatal substance use and offspring ADHD symptoms, a causal prenatal (intrauterine) effect only exists for maternal prenatal substance use. b) Polygenic risk score analysis was conducted with maternal genetic variants as proxies for prenatal smoking, alcohol and caffeine consumption (3 separate analyses, with polygenic risk scores specific to the substance used).